Photosynthesis is the main biological process driven by light, which converts light energy into chemical one that can be later used to fuel organisms’ activities. In this paper, I describe molecular principles underlying this process as well as involved therein photosynthetic pigments and membrane proteins complexes. Photosynthetic processes are widely used as an inspiration for artificial ones, not only by attempts to mimick the natural processes but also by building simpler ones from artificial components. Research developments in this field may lead to to the discovery of an efficient, cheap and environmental friendly photocell unit.